Has my chin implant been improperly placed?

Thank you for your question. Occasionally a chin implant can migrate if it is not secured with a mini-screw. A 3-D CT scan would be helpful to determine if the implant is properly positioned or migrated. It is possible that the implant is not best size for your face. If you are not satisfied with your result, return to your surgeon or go for a second opinion. Good luck.

...this is common and frequent with chin implants in spite their popularity.
Chin implants have many disadvantages:
-visibility, static or with facial gestures / smiliing
-artificialness, fake look, evidence of implant presence

-limited lack of versatility, they do not provice vertical modifications neither reductions
-common infections
-common dislocations
-possible nerve irritation and pain
-short lifetime
So sooner than later they are normally removed, or exchanged by an osseous genioplasty.
Why
so popular (chin implants) then? Simple answer: they are technically
accessible to all surgeons, little training is required, can be done
under local and sometimes office based procedures, they are cheap.
I recommend you cosider future replacement by osseous geniplasty performed by a well-trained surgeon.
Osseous geniplasties are more expensive and need good skills, true, but when performed they produce lifetime results, safe, stable overtime, very low rate of complications, versatile three-dimensional modifications (augmentation or reduction, vertical, horizontal and depth), low rate of reinterventions, etc.

if it is bothering you then might want to remove it and have a sliding genioplasty. It is your own bone and won't move.